Dr. Anthony Fauci called President-elect Joe Biden's promise to administer 100 million COVID-19 shots in the first 100 days of his term "quite feasible" during an interview with NBC's "Today" show Friday. He said he hopes the United States can get to 70% or 80% vaccination within several months.

Part of the distribution holdup, according to Fauci, has been careful prioritization by states. "If you have a dose, give it," he urged states. "Don't be so rigid as to those early designations."

Reaching those goals, however, depends on vaccine uptake. "When a vaccine becomes available, get vaccinated,” Fauci pleaded with the public.

-ABC News' Anne Flaherty contributed to this report.

U.S. President-elect Joe Biden has chosen Dr. David Kessler, former commissioner of the Food and Drug Administration (FDA), to help lead the federal government's COVID-19 vaccine initiative.

Kessler, a pediatrician and lawyer who headed the FDA from 1999 to 1997 under the Bush and Clinton administrations, will replace Dr. Moncef Slaoui, who is the current chief science officer to Operation Warp Speed.

Biden also announced several other appointees who will join his incoming administration's COVID-19 response team.

"We are in a race against time, and we need a comprehensive strategy to quickly contain this virus," Biden said in a statement Thursday. "The individuals announced today will bolster the White House’s COVID-19 Response team and play important roles in carrying out our rescue plan and vaccination program. At a time when American families are facing numerous challenges I know these public servants will do all that is needed to build our nation back better."

There were 5,534 newly confirmed cases of COVID-19 and a record 81 deaths from the disease registered in Moscow on Thursday, according to Russia's coronavirus response headquarters.

In total, the Russian capital has reported 882,962 confirmed cases with 12,322 deaths, according to the coronavirus response headquarters.

With more than 3.4 million confirmed cases, Russia has the fourth highest cumulative total in the world, after the United States, India and Brazil, according to a real-time count kept by Johns Hopkins University.

ABC News' Alina Lobzina contributed to this report.

There were 229,386 new cases of COVID-19 confirmed in the United States on Thursday, according to a real-time count kept by Johns Hopkins University.

It's the 10th consecutive day that the country has reported more than 200,000 new cases. Thursday's tally is less than the country's all-time high of 302,506 newly confirmed infections on Jan. 2, Johns Hopkins data shows.

An additional 3,769 new deaths from COVID-19 were registered nationwide on Thursday, down from a peak of 4,462 fatalities logged on Jan. 12, according to Johns Hopkins data.

COVID-19 data may be skewed due to possible lags in reporting over the holidays followed by a potentially very large backlog.

A total of 23,314,238 people in the U.S. have been diagnosed with COVID-19 since the pandemic began, and at least 388,705 have died, according to Johns Hopkins data. The cases include people from all 50 U.S. states, Washington, D.C., and other U.S. territories as well as repatriated citizens.

Much of the country was under lockdown by the end of March as the first wave of pandemic hit. By May 20, all U.S. states had begun lifting stay-at-home orders and other restrictions put in place to curb the spread of the novel coronavirus. The day-to-day increase in the country's cases then hovered around 20,000 for a couple of weeks before shooting back up over the summer.

The numbers lingered around 40,000 to 50,000 from mid-August through early October before surging again to record levels, crossing 100,000 for the first time on Nov. 4, then reaching 200,000 on Nov. 27 before topping 300,000 on Jan. 2.

A new, more infectious variant of the novel coronavirus that was first detected in the United Kingdom has now been discovered in Mexico.

The strain, called B117, was confirmed in a 56-year-old foreign citizen who had traveled from Amsterdam to Mexico City on Dec. 28, and then to the northeastern city of Matamoros the following day. The individual was asymptomatic when he arrived in the country, according to Mexico's director general of epidemiology, Jose Luis Alomia Zegarra.

After testing positive for COVID-19, the man was admitted to a Mexican hospital last week where he remains intubated, Zegarra said.

Genomic sequencing of the patient's sample that tested positive for COVID-19 revealed its B117 lineage. More than 500 suspected cases of the U.K. variant have been tested in Mexico, but this is the country's first verified case, according to Zegarra.

Mexican health authorities are tracking contacts of the patient, including people who traveled on the same flight. Two individuals who showed symptoms have since tested negative for COVID-19, while another 31 are asymptomatic and remain in isolation. Officials have been unable to locate 12 others, Zegarra said.

The highly contagious strain has become prevalent in London and other parts of southeast England, after first being identified in the English county of Kent in September. The B117 variant has since been detected in over a dozen other countries.